Retired Justice John Paul Stevens is citing one of his own opinions as offering legal support for President Obama’s health care law.

Stevens referred to the opinion, Gonzales v. Raich, in an interview with Bloomberg News. The 6-3 decision held the federal government had commerce clause authority to ban medical marijuana, even when the drug doesn’t cross state lines.

“To the extent that the commerce clause is an issue in the case, it just seems to me very similar” to the medical marijuana dispute, Stevens told Bloomberg. Justice Antonin Scalia and Anthony M. Kennedy sided with Stevens in the case, though Scalia wrote separately.

Stevens said Scalia might be willing to uphold the health-care law, even if he disagrees with its substance.